I agree you would be butchering two machines to produce one mongrel and one pile of scrap. It is the sort of thing that is only done by somebody desperate for a cheap reel mower, not by a person who has any kind feelings toward Scott Bonnar classics. I think it would not be very difficult, but the scrap-to-useful-output ratio would be awful.
Unfortunately the same line of thinking (emphasis on preserving our mower heritage) says you have to keep the Villiers engine and tidy up the smaller mower to make it usable. Whether you tidy up the electric machine as well, or just store it safely for the next generation, is a secondary question.
